prosody
d01254d5a825
net/websocket/frames.lua

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net/websocket/frames.lua @ 6898:d01254d5a825

net.websocket.frames: Pack and unpack 64bit ints without overflows (lua-bitop/bit32 are 32bit)
author Kim Alvefur <zash@zash.se>
date Tue, 06 Oct 2015 18:03:04 +0200
parent 6897:8972b1a96526
child 6899:5f3da8b00b9b
comparison
equal deleted inserted replaced
6897:8972b1a96526 6898:d01254d5a825
28 return l1*256 + l2; 28 return l1*256 + l2;
29 end 29 end
30 -- FIXME: this may lose precision 30 -- FIXME: this may lose precision
31 local function read_uint64be(str, pos) 31 local function read_uint64be(str, pos)
32 local l1, l2, l3, l4, l5, l6, l7, l8 = s_byte(str, pos, pos+7); 32 local l1, l2, l3, l4, l5, l6, l7, l8 = s_byte(str, pos, pos+7);
33 return lshift(l1, 56) + lshift(l2, 48) + lshift(l3, 40) + lshift(l4, 32) 33 local h = lshift(l1, 24) + lshift(l2, 16) + lshift(l3, 8) + l4;
34 + lshift(l5, 24) + lshift(l6, 16) + lshift(l7, 8) + l8; 34 local l = lshift(l5, 24) + lshift(l6, 16) + lshift(l7, 8) + l8;
35 return h * 2^32 + l;
35 end 36 end
36 local function pack_uint16be(x) 37 local function pack_uint16be(x)
37 return s_char(rshift(x, 8), band(x, 0xFF)); 38 return s_char(rshift(x, 8), band(x, 0xFF));
38 end 39 end
39 local function get_byte(x, n) 40 local function get_byte(x, n)
40 return band(rshift(x, n), 0xFF); 41 return band(rshift(x, n), 0xFF);
41 end 42 end
42 local function pack_uint64be(x) 43 local function pack_uint64be(x)
43 return s_char(rshift(x, 56), get_byte(x, 48), get_byte(x, 40), get_byte(x, 32), 44 local h = band(x / 2^32, 2^32-1);
44 get_byte(x, 24), get_byte(x, 16), get_byte(x, 8), band(x, 0xFF)); 45 return s_char(get_byte(h, 24), get_byte(h, 16), get_byte(h, 8), band(h, 0xFF));
46 get_byte(x, 24), get_byte(x, 16), get_byte(x, 8), band(x, 0xFF);
45 end 47 end
46 48
47 local function parse_frame_header(frame) 49 local function parse_frame_header(frame)
48 if #frame < 2 then return; end 50 if #frame < 2 then return; end
49 51